Prefillable intradermal delivery device with hidden needle and passive shielding

ABSTRACT

An intradermal needle assembly ( 10 ) for injecting a substance into the skin of an animal is disclosed. A hub ( 16 ) is attachable to a container ( 12 ) storing the substance. A needle ( 18 ) is supported by the hub ( 16 ) and has a forward tip ( 20 ) extending away from the hub ( 16 ). A limiter ( 22 ) surrounds the needle ( 18 ) and extends away from the hub ( 16 ) toward the forward tip ( 20 ) of the needle ( 18 ). The limiter ( 22 ) includes a generally flat skin engaging surface ( 24 ) extending in a plane generally perpendicular to an axis of the needle ( 18 ) and is adapted to be received against the skin ( 26 ) to administer an intradermal injection. The limiter ( 22 ) is movable between a first position ( 28 ), wherein the skin engaging surface ( 24 ) shields the needle ( 18 ), and a second position ( 30 ), wherein the forward tip ( 20 ) extends beyond the skin ( 26 ) upon depressing the skin engaging surface ( 24 ) against the skin ( 26 ).

FIELD OF THE INVENTION

The present invention relates generally to an intradermal injectionassembly having a limiter positioned to limit the penetration of aforward tip of a needle cannula into the dermis of an animal. Moreparticularly, the present invention relates to an intradermal deliveryassembly having an integrated, passive shielding device to shield theforward tip of the needle cannula prior to and subsequent toadministering the intradermal injection.

BACKGROUND OF THE INVENTION

Intradermal injections are used for delivering a variety of substances.Many of these substances have proven to be more effectively absorbedinto or react with the immune response system of the body when injectedintradermally. An intradermal injection is made by delivering thesubstance into the epidermis and upper layer of the dermis. Below thedermis layer is subcutaneous tissue (also sometimes referred to as thehypodermis layer) and muscle tissue, in that order. There isconsiderable variation in the skin thickness both between individualsand within the same individual at different sites of the body.Generally, the outer skin layer epidermis has a thickness of between 50to 200 microns, and the dermis, the inner and thicker layer of the skin,has a thickness between 1.5 and 3.5 mm. Therefore, a needle cannula thatpenetrates the skin deeper than about 3.0 mm has a potential of passingthrough the dermis layer of the skin making the injection into thesubcutaneous region, which may result in an insufficient immuneresponse, especially where the substance to be delivered intradermallyhas not been indicated for subcutaneous injection. Also, the needlecannula may penetrate the skin at too shallow a depth to deliver thesubstance and result in what is commonly known in the art as “wetinjection” due to reflux of the substance from the injection site.

Due to the inherent limitations of the standard needle assembly, thestandard procedure for making an intradermal injection is known to bedifficult to perform, and therefore dependent upon experience andtechnique. This procedure is recommended to be performed by stretchingthe skin, orienting the needle bevel to face upwardly, and inserting a26 gauge short bevel needle cannula to deliver a volume of 0.5 ml orless of the substance into the skin of the animal with the needlecannula being inserted into the skin at an angle varying from around 10to 15° to form a blister or wheel in which the substance is deposited orotherwise contained.

The technique utilized to perform the standard intradermal injection isdifficult and requires the attention of a trained nurse or medicaldoctor. Inserting the needle to a depth greater than about 3.0 mmtypically results in a failed intradermal injection because thesubstance being expelled through the cannula will be injected into thesubcutaneous tissue of the animal. As disclosed in pending U.S. patentapplication Ser. Nos. 09/834,438 and 09/417,671, an intradermal needleassembly has been developed for use with a prefillable container havinga reservoir capable of storing a substance for injection into the skinof an animal. A hub portion, which is attachable to the prefillablecontainer storing the substance, supports a needle cannula having aforward tip extending away from the hub portion. A limiter portionsurrounds the needle cannula and extends away from the hub portiontowards the forward tip of the needle cannula. The limiter includes agenerally flat skin engaging surface extending in a plane generallyperpendicular to an axis of the needle cannula and is adapted to bereceived against the skin of the animal to administer the intradermalinjection of the substance. The needle forward tip extends beyond theskin engaging surface a distance of approximately 0.5 to 3.0 mm.Therefore, the limiter portion limits penetration of the needle into thedermis layer of the skin of the animal so that the vaccine is injectedinto the dermis layer of the animal.

The devices that have been adapted to administer an intradermalinjection, and other devices utilizing needle cannulas with sharp tipsto inject substances into the skin of the animal have typically includeda fixed design where each of the components of the assembly arestationary relative to the other components. Therefore, the forward tipof the needle cannula remains exposed even after administration of theintradermal injection. With the advent of viral diseases transmittedthrough the contact of body fluid, it has become desirable to developneedle shielding devices that would prevent unintended access to theneedle cannula subsequent to administering an injection. While thesetypes of devices have been introduced to the marketplace for standardinjection assemblies, they have not been developed in combination withan injection device adapted to administer an intradermal injectionthrough the use of a limiter as described above.

In addition, it has become increasingly desirable to hide the needleprior to use to address any potential concerns by patients of seeing anexposed needle prior to use.

Therefore, it would be desirable to introduce an intradermal deliveryassembly utilizing a limiter, as set forth above, to limit thepenetration of a needle cannula into the dermis of an animal incombination with a shielding component to prevent unintended contactwith the needle subsequent to administration of the intradermalinjection, and to hide the needle prior to use.

SUMMARY OF THE INVENTION AND ADVANTAGES

In contrast to the intradermal injection assemblies that have beendisclosed in the past, it has been determined by the Applicant that itis feasible to include a shielding device with the intradermal assemblythat can provide the benefit of shielding the forward tip of the needlecannula both prior to and subsequent to administering an intradermalinjection.

The intradermal needle assembly of the present invention is for use witha prefillable container that includes a reservoir capable of storing asubstance for injection into the skin of an animal. A hub portion isattachable to the prefillable container storing the substance andsupports a needle cannula. The needle cannula includes a forward tipextending away from the hub portion. A limiter surrounds the needlecannula and extends away from the hub portion towards the forward tip ofthe needle cannula. The limiter includes a generally flat skin engagingsurface extending in a plane generally perpendicular to an axis of theneedle cannula and is adapted to be received against the skin of theanimal to administer an intradermal injection of the substance.

The limiter is moveable between at least a first position where the skinengaging surface shields the forward tip of the needle cannula, and asecond position where the forward tip extends beyond the skin engagingsurface a distance sufficient to administer the substance into thedermis layer of the animal upon depression of the skin engaging surfaceagainst the skin of the animal. The limiter is biased toward the firstposition by a spring means that is compressible upon depressing the skinengaging surface against the skin of the animal. Therefore, afteradministering the intradermal injection and withdrawing the skinengaging surface from the skin of the animal, the limiter returns andlocks to the first position to shield the forward tip of the needlecannula.

Alternatively, the limiter is circumscribed by a shield that is biasedtoward the forward tip of the needle cannula by the spring means. Inthis embodiment, the shield is moveable between the first position wherethe forward tip of the needle cannula is shielded, and the secondposition where the forward tip of the needle cannula extends beyond theskin engaging surface a distance sufficient to administer the substanceinto the dermis layer of the animal upon depression of the skin engagingsurface against the skin of the animal. Accordingly, the limiter isfixed relative to the needle cannula and the hub portion and only theshield is moveable between the first and second positions.

The embodiments of the subject invention set forth above provide thebenefit of administering an intradermal injection utilizing a depthlimiting device that limits the penetration of the forward tip of theneedle cannula into the dermis layer of the animal simplifying themethod of administering the intradermal injection. Further, a passiveshielding device is provided which shields the forward tip of the needlecannula both prior to and subsequent to administering the intradermalinjection. Thus, the intradermal needle assembly prevents exposure tothe forward tip of the needle cannula prior to administering theinjection maintaining sterilization, and subsequent to administering theinjection reducing the potential for a biohazard resulting from contactwith the needle cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is cross-sectional view of a first embodiment of the presentinvention showing a needle limiter capable of shielding a needle cannulawhile located in a first position;

FIG. 2 is cross-sectional view of the first embodiment of the presentinvention showing a needle limiter limiting the injection depth of theneedle cannula while located in a second position;

FIG. 3 is cross-sectional view of the first embodiment of the presentinvention showing a needle limiter shielding a needle cannula whilelocked in the first position subsequent to administering the intradermalinjection;

FIG. 4 is an exploded view of the first embodiment of the presentinvention;

FIGS. 5 and 6 show an alternate embodiment of the present invention inthe first and second positions;

FIG. 7 shows the alternate embodiment locked in the first positionsubsequent to administering the intradermal injection;

FIG. 8 shows a further embodiment of the present invention with a sleevecapable of shielding the needle cannula while in a first position;

FIG. 9 shows the further embodiment with the sleeve located in aretracted position while administering the intradermal injection;

FIG. 10 shows the further embodiment locked in the first positionsubsequent to administering the intradermal injection;

FIGS. 11 and 12 show a still further embodiment of the present inventionhaving a limiter slidably attached to a hub and being capable ofshielding the needle cannula prior to and subsequent to administeringthe intradermal injection; and

FIG. 13 shows the still further embodiment locked in the first positionsubsequent to administering the intradermal injection.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An intradermal needle assembly of the subject invention is generallyshown at 10 of FIGS. 1, 2 and 3. The assembly includes a prefillablecontainer 12 having a reservoir 14 capable of storing a substance forinjection into the skin of an animal. A hub portion 16 is attachable tothe prefillable container 12 and supports a needle cannula 18 having aforward tip 20 extending away from the hub portion 16.

A limiter 22 surrounds the needle cannula and extends away from the hubportion 16 toward the forward tip 20 of the needle cannula 18. Thelimiter 22 includes a generally flat skin engaging surface 24 extendingin a plane generally perpendicular to an axis of the needle cannula 18.The skin engaging surface 24 is adapted to be received against the skin26 of an animal to administer an intradermal injection of the substance.

The limiter 22 is moveable between a first position 28 as shown in FIG.1 and a second position 30 as shown in FIG. 2. When the limiter islocated in the first position 28, the skin engaging surface 24 shieldsthe forward tip 20 of the needle cannula 18. When the limiter 22 islocated in the second position 30, the forward tip 20 of the needlecannula 18 extends beyond the skin engaging surface 24 a distancesufficient to administer the substance disposed in the reservoir 14 intothe dermis layer 26 of the animal. The assembly 10 includes a plunger 32having a stopper 35 slideably disposed within the reservoir 14 of theprefillable container 12. As known to those of skill in the art, bydepressing the plunger 32, the stopper 35 slides inwardly of thereservoir 14 causing the substance disposed in the reservoir 14 to beexpelled from the prefillable container 12 through the needle cannula 18into the skin 26 of the animal.

When the limiter 22 is disposed in the second position 30, the forwardtip 20 of the needle cannula 18 extends beyond the skin engaging surface24 a distance of approximately 0.5 to 3.0 mm. Therefore, the penetrationof the needle cannula 18 into the dermis layer of the skin 26 is limitedso that the substance is injected into the dermis layer 26 of theanimal. The limiter 22 includes at least one stop 32 that is engageablewith a counter stop 34 disposed upon the hub portion 16 to terminatemovement of the limiter 22 rearwardly of the forward tip 20, therebyallowing only 0.5 to 3.0 mm of the needle cannula 18 to be exposed.

The limiter 22 is slideably disposed within a sleeve 36. Accordingly,the limiter 22 is concentrically aligned between the sleeve 36 and theprefillable container 12. The limiter 22 is biased outwardly of thesleeve 36 by a spring means 38. The spring means is represented in thefigures as a coil spring, however, it should be understood by those ofskill in the art that any resilient member may be used to bias thelimiter 22 outwardly of the sleeve 36.

The spring means 38 is compressed between the limiter 22 and a rim 40 ofthe prefillable container 12 disposed upon an end of the prefillablecontainer 12 opposite the limiter 22. The rim 40 of the prefillablecontainer 12 is fixedly attached to the sleeve 36 by a plurality ofsnaps 42. A plug 44 is engageable with the needle cannula 18 to seal theprefillable container 12 at the needle cannula 18. The plug 44 isinserted through a central aperture 45 in the skin engaging surface 24that is axially aligned with the needle cannula 18. The plug 44 isremoved prior to administering the intradermal injection.

A least one catch 47 is disposed upon a side of the limiter 22 and isengageable with a slot 49 disposed in a side of the sleeve 36. The catch47 is biased to engage the slot 49 when the limiter 22 returns to thefirst position 28 subsequent to administering the injection to preventthe forward tip 20 from being re-exposed. This is best represented inFIG. 3.

FIGS. 5, 6 and 7 show an alternate embodiment of the subject assemblygenerally at 46. At least one sleeve stop 48 is positioned rearwardly ofthe limiter 22 inside the sleeve 36. The sleeve stop 48 is spaced fromthe limiter 22 when the limiter is located in the first position 28.Movement of the limiter by depressing the skin engaging surface 24against the skin 26 of the animal is terminated when the limiter 22abuts the sleeve stop 48 locating the limiter 22 in the second position30. As set forth above, when the limiter 22 is located in the secondposition 30, the forward tip 20 of the needle cannula 18 extends beyondthe skin engaging surface 24 a distance between 0.5 and 3.0 mm. Uponwithdrawing the alternate embodiment 46 from the skin 26 of the animal,the limiter 22 returns to the first position 28 shielding the needlecannula 18.

A least one catch 51 is disposed upon a side of the limiter 22 and isengageable with a slot 53 disposed in a side of the sleeve 36. The catch51 is biased to engage the slot 53 when the limiter 22 returns to thefirst position 28 subsequent to administering the injection to preventthe forward tip 20 from being re-exposed. This is best represented inFIG. 7.

FIGS. 8 and 9 show a further alternate embodiment of the presentinvention generally at 50. A limiter portion 52 is affixed to the hubportion 16 in a stationary manner. A shield 54 circumscribes the limiter52 and is concentrically aligned between the sleeve 36 and theprefillable container 12.

The shield 54 is slideable between the first position 28 and the secondposition 30. The spring means 38 biases the shield 54 towards the firstposition 28. The shield 54 shields the forward tip 20 of the needlecannula 18 when in the first position 28. The shield includes a skinengaging surface 56 that aligns with a generally flat skin engagingsurface 58 of the stationary limiter portion 52 when the shield 54 islocated in the second position 30. Upon depressing the limiter skinengaging surface 58 against the skin 26 of an animal, the shield 54moves inwardly of the sleeve 36 exposing 0.5 to 3.0 mm of the needlecannula enabling the intradermal injection to be made into the skin 26of the animal. Upon withdrawing the assembly 50 from the skin 26 of theanimal, the shield 54 moves outwardly of the sleeve 36 returning to thefirst position 28.

An abutting member 62 abuts the hub portion 16 preventing the shield 54from moving beyond the first position 28 or being ejected from theassembly 50 by the spring means 38.

A least one catch 55 is disposed upon a side of the limiter 22 and isengageable with a slot 57 disposed in a side of the sleeve 36. The catch55 is biased to engage the slot 57 when the limiter 22 returns to thefirst position 28 subsequent to administering the injection to preventthe forward tip 20 from being re-exposed. This is best represented inFIG. 10.

A plug 63 is engageable with the needle cannula 18 to seal theprefillable container 12 at the needle cannula 18. The plug 63 isinserted through a central aperture 59 in the skin engaging surface 56that is axially aligned with the needle cannula 18. The plug 63 isremoved prior to administering the intradermal injection.

An additional alternate embodiment is generally shown at 64 in FIGS. 11through 13. An alternate limiter 66 circumscribes the hub portion 16 andslideably engages the prefillable container 12.

The alternate limiter 66 is moveable between a first position 68 and asecond position 70 relative to the hub portion 16. A skin engagingsurface 72 as disposed upon the limiter 66 is engageable with the skinof the animal to administer the intradermal injection. The spring means38 is compressed between the hub portion 16 and a rear side of the skinengaging surface 72. The spring means 38 biases the alternate limiter 66to the first position 68. Upon depression of the skin engaging surface72 against the skin 26 of the animal, the spring means 38 is compressedallowing the alternate limiter 66 to move from the first position 68 tothe second position 70.

The hub portion 16 includes at least one catch 67 extending towards theforward tip 20 of the needle cannula 16. The catch 67 engages a slot 69disposed in a wall of the limiter 66 to prevent the limiter 66 frombeing moved to second position 70 from the first position subsequent toadministering the injection. A plurality of catches 67 may also be usedto improve the stability of the limiter 66. A stop 71 is disposed uponan inner wall of the limiter and is engageable with the catch 67 toprevent the limiter 66 from being ejected from the assembly 64 by thespring means 38.

The forward tip 20 of the needle cannula 18 extends beyond the skinengaging surface 72 a distance of 0.5 to 3.0 mm when the alternatelimiter 66 is disposed in the second position 70.

As shown in FIGS. 10 and 11, the alternate limiter 66 includes a stop 74disposed upon an inner surface and is engageable with a rear member 76of the hub portion 16. The stop 74 prevents the alternate limiter 66from moving beyond the second position 70. Alternatively, as shown inFIGS. 12 and 13, a leading edge 78 of the hub portion 16 engages aflange 80 directed rearwardly from the skin engaging surface 72 toprevent the limiter portion 66 from moving beyond the second position. Aplug 82 is engageable with the needle cannula 18 to seal the prefillablecontainer 12 at the needle cannula. The plug 82 is inserted through acentral aperture 84 in the skin engaging surface 72 that is axiallyaligned with the needle cannula 18. The plug 82 is removed prior toadministering the intradermal injection.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims, whereinreference numerals are merely for convenience and are not to be in anyway limiting, the invention may be practiced otherwise than asspecifically described.

1. An intradermal needle assembly for use with a prefillable containerhaving a reservoir capable of storing a substance for injection into theskin of an animal comprising: a hub portion being attachable to theprefillable container; a needle cannula supported by said hub portionand having a forward tip extending away from said hub portion; and alimiter surrounding said needle cannula and extending away from said hubportion toward said forward tip of said needle cannula, said limiterincluding a generally flat skin engaging surface extending in a planegenerally perpendicular to an axis of said needle cannula and adapted tobe received against the skin of the animal to administer an intradermalinjection of the substance; said limiter being movable between at leasta first position, wherein said skin engaging surface shields saidforward tip of said needle cannula, and a second position, wherein saidforward tip extends beyond said skin engaging surface a distancesufficient to administer the substance into the dermis layer of theanimal upon depression of said skin engaging surface against the skin ofthe animal.
 2. An assembly as set forth in claim 1, further comprisingspring means for biasing said limiter towards said first position.
 3. Anassembly as set forth in claim 1, wherein said forward tip of saidneedle cannula extends beyond said skin engaging surface a distanceranging from approximately 0.5 mm to 3.0 mm when said limiter is locatedin said second position thereby limiting penetration of said needle intothe dermis layer of skin of the animal so that the substance is injectedinto the dermis layer of the animal.
 4. An assembly as set forth inclaim 3, further comprising a sleeve having the prefillable containerfixedly disposed therein with said limiter slideably protrudingtherefrom.
 5. An assembly as set forth in claim 4, wherein said sleeveincludes a stop positioned to prevent said limiter from sliding beyondsaid second position.
 6. An assembly as set forth in claim 1, furthercomprising catch engageable to prevent said limiter from moving fromsaid first position to said second position subsequent to administeringthe intradermal injection.
 7. An assembly as set forth in claim 1,wherein the prefillable container includes a rim disposed on an endopposite said hub and said spring means is provided between said rim andsaid limiter.
 8. An assembly as set forth in claim 2, wherein saidspring means is provided between said hub and said limiter therebybiasing said limiter towards said first position.
 9. An assembly as setforth in claim 8, further comprising a stop positioned to prevent saidlimiter from sliding beyond said second position.
 10. An assembly as setforth in claim 9, wherein said hub includes a catch engageable with saidlimiter when said limiter is returned to said first position therebypreventing said limiter from moving from said first position to saidsecond position subsequent to administering the intradermal injection.11. An assembly as set forth in claim 1, further comprising a plugcomprising a resilient material applied over said forward tip of saidneedle cannula thereby sealing said prefillable container at said needlecannula.
 12. An intradermal needle assembly for use with a prefillablecontainer having a reservoir capable of storing a substance forinjection into the skin of an animal comprising: a hub portion beingattachable to the prefillable container; a needle cannula supported bysaid hub portion and having a forward tip extending away from said hubportion; a limiter portion surrounding said needle cannula and extendingaway from said hub portion toward said forward tip of said needlecannula, said limiter including a generally flat skin engaging surfaceextending in a plane generally perpendicular to an axis of said needlecannula and adapted to be received against the skin of the animal toadminister an intradermal injection of the substance, said needleforward tip extending beyond said skin engaging surface a distancesufficient to enable injection of the substance into the dermis layer ofthe animal; and a shield circumscribing said limiter and being biasedtowards said forward tip of said needle cannula with at least a firstposition wherein said shield shields said forward tip, and a secondposition wherein said shield exposes said forward tip.
 13. An assemblyas set forth in claim 12, wherein said needle cannula extends beyondsaid skin engaging surface a distance ranging from approximately 0.5 mmto 3.0 mm.
 14. An assembly as set forth in claim 13, further comprisinga sleeve having the prefillable container fixedly disposed therein withsaid shield slideably protruding therefrom.
 15. An assembly as set forthin claim 12, further comprising a spring means disposed within saidsleeve and biasing said shield towards said forward tip of said needlecannula.
 16. An assembly as set forth in claim 15, wherein theprefillable container includes a rim disposed on an end opposite fromsaid hub whereby said spring means is compressed between said rim andsaid shield.
 17. An assembly as set forth in claim 12, wherein saidshield is moveable between said first position and said second positionby depressing said skin engaging surface against the skin of the animal.18. An assembly as set forth in claim 12, wherein said sleeve includes astop positioned to prevent said limiter from sliding beyond said secondposition.
 19. An assembly as set forth in claim 18, further comprising acatch engageable when said shield is returned to said first positionthereby preventing said shield from moving from said first position tosaid second position subsequent to administering the intradermalinjection.
 20. An assembly as set forth in claim 12, further comprisinga plug comprising a resilient material applied over said forward tip ofsaid needle cannula thereby sealing said prefillable container at saidneedle cannula.
 21. A method of administering an intradermal injectioninto the skin of an animal comprising the steps of: providing a drugdelivery device including a needle cannula having a forward needle tip,said needle cannula being in fluid communication with a substancecontained in said drug delivery device; shielding said forward tip ofsaid needle cannula with a shielding surface by locating said shieldingsurface in a first position; depressing said shielding surface againstthe skin of an animal thereby moving said shielding surface to a secondposition and exposing said forward tip of said needle cannula a lengthsufficient to administer an intradermal injection; inserting saidforward tip into the skin of the animal and engaging the surface of theskin with said skin engaging shielding surface such that said shieldingsurface limits penetration of the forward tip into the dermis layer ofthe skin of the animal; expelling the substance from said drug deliverydevice through said forward tip into the dermis of the animal; andretracting said shielding surface from the skin of the animal therebyallowing said shielding surface to move from said second position tosaid first position thereby shielding said forward tip of said needlecannula.
 22. A method as set forth in claim 21 wherein said step ofexposing said forward tip of said needle cannula is further defined asexposing a length of said needle cannula equal to approximately 0.5 mmto approximately 3.0 mm.
 23. A method as set forth in claim 21 whereinsaid shielding surface is further defined as having a fixed angle oforientation relative to said needle cannula.
 24. A method as set forthin claim 21 wherein said shielding surface is further defined as beingadapted to be received against the skin of an animal.
 25. A method asset forth in claim 21 further including the step of securing saidshielding surface in said first position subsequent to expelling thesubstance from said drug delivery device into the dermis of the animalto prevent said forward tip of said needle cannula from beingre-exposed.
 26. A method as set forth in claim 21 further including thestep of biasing said shielding surface towards said first position. 27.A method as set forth in claim 21 further including the step ofproviding a plunger being slideably disposed with said prefillablecontainer and being depressible for expelling the substance from thecontainer.
 28. A method as set forth in claim 21 further including thestep of unsealing said needle cannula prior to depressing said shieldingsurface against the skin of the animal.
 29. An intradermal needleassembly for a prefillable container having a reservoir capable ofstoring a substance for injection into the skin of an animal comprising:a hub portion provided on the prefillable container; a needle cannulasupported by said hub portion and having a forward tip extending awayfrom said hub portion; and a limiter surrounding said needle cannula andextending away from said hub portion toward said forward tip of saidneedle cannula, said limiter including a generally flat skin engagingsurface extending in a plane generally perpendicular to an axis of saidneedle cannula, said limiter being movable between a first position inwhich said forward tip of said needle cannula is contained within saidlimiter, and a second position in which said forward tip of said needlecannula extends beyond said skin engaging surface a distance sufficientto administer the substance into the dermis layer of the animal upondepression of said skin engaging surface against the skin of the animal.30. An assembly as set forth in claim 29, further comprising springmeans for biasing said limiter toward said first position.
 31. Anassembly as set forth in claim 29, wherein said forward tip of saidneedle cannula extends beyond said skin engaging surface a distanceranging from approximately 0.5 mm to 3.0 mm when said limiter is locatedin said second position thereby limiting penetration of said needle intothe dermis layer of skin of the animal so that the substance is injectedinto the dermis layer of the animal.
 32. An assembly as set forth inclaim 31, further comprising a sleeve having the prefillable containerfixedly disposed therein with said limiter slideably protrudingtherefrom.
 33. An assembly as set forth in claim 32, wherein said sleeveincludes a stop positioned to prevent said limiter from sliding beyondsaid second position.
 34. An assembly as set forth in claim 29, furthercomprising a catch engageable to prevent movement of said limiter fromsaid first position to said second position subsequent to administeringthe intradermal injection.
 35. An assembly as set forth in claim 29,wherein the prefillable container includes a rim disposed on an endopposite said hub and wherein said spring means is provided between saidrim and said limiter.
 36. An assembly as set forth in claim 30, whereinsaid spring means is provided between said hub and said limiter therebybiasing said limiter towards said first position.
 37. An assembly as setforth in claim 36, further comprising a stop positioned to prevent saidlimiter from moving beyond said second position.
 38. An assembly as setforth in claim 37, wherein said hub includes a catch engageable withsaid limiter when said limiter is returned to said first positionthereby preventing said limiter from moving from said first position tosaid second position subsequent to administering the intradermalinjection.
 39. An assembly as set forth in claim 29, further comprisinga plug comprising a resilient material applied over said forward tip ofsaid needle cannula thereby sealing said prefillable container at saidneedle cannula.
 40. An intradermal needle assembly for a prefillablecontainer having a reservoir capable of storing a substance forinjection into the skin of an animal comprising: a hub portion providedon the prefillable container; a needle cannula supported by said hubportion and having a forward tip extending away from said hub portion; alimiter portion surrounding said needle cannula and extending away fromsaid hub portion toward said forward tip of said needle cannula, saidlimiter including a generally flat skin engaging surface extending in aplane generally perpendicular to an axis of said needle cannula, saidneedle forward tip extending beyond said skin engaging surface adistance sufficient to enable injection of the substance into the dermislayer of the animal; and a shield circumscribing said limiter and beingmovable between a first position, in which said forward tip of saidneedle cannula is shielded by said shield, and a second position, inwhich said forward tip of said needle cannula is exposed, said shieldbeing biased towards said a first position.
 41. An assembly as set forthin claim 40, wherein said needle cannula extends beyond said skinengaging surface a distance ranging from approximately 0.5 mm to 3.0 mm.42. An assembly as set forth in claim 41, further comprising a sleevehaving the prefillable container fixedly disposed therein with saidshield slideably protruding therefrom.
 43. An assembly as set forth inclaim 40, further comprising a spring means disposed within said sleeveand biasing said shield towards said forward tip of said needle cannula.44. An assembly as set forth in claim 43, wherein the prefillablecontainer includes a rim disposed on an end opposite from said hubwhereby said spring means is compressed between said rim and saidshield.
 45. An assembly as set forth in claim 40, wherein said shield ismoveable between said first position and said second position bydepressing said skin engaging surface against the skin of the animal.46. An assembly as set forth in claim 40, wherein said sleeve includes astop positioned to prevent said limiter from sliding beyond said secondposition.
 47. An assembly as set forth in claim 46, further comprising acatch engageable when said shield is returned to said first positionthereby preventing said shield from moving from said first position tosaid second position subsequent to administering the intradermalinjection.
 48. An assembly as set forth in claim 40, further comprisinga plug comprising a resilient material applied over said forward tip ofsaid needle cannula thereby sealing said prefillable container at saidneedle cannula.
 49. An assembly as set forth in claim 1, furthercomprising a prefillable container.
 50. An assembly as set forth inclaim 12, further comprising a prefillable container.
 51. An assembly asset forth in claim 29, further comprising a prefillable container. 52.An assembly as set forth in claim 40, further comprising a prefillablecontainer.